[Isolation and fractionation of the nuclear matrix from cultured cells]

A new method for the isolation of tissue culture cell nuclei is presented which involves incubation of the nuclei in the presence of Cu2+- or Zn2+-ions. This method eliminates the danger of nuclear aggregation and permits nuclear matrix isolation and subsequent fractionation. Stabilization of the inner matrix by Cu2-ions permits analysis of the role of nucleic acids in the maintenance of the matrix structure. It is shown that solubilization of more than 95% of matrix-bound DNA and more than 90% of matrix-bound RNA did not cause any significant changes in the nuclear matrix structure.